PATCH: Expansion of \c escape sequences

PATCH: Expansion of \c escape sequences

[Thorsten Dahlheimer]

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Hi,

I've noticed that in contexts where escape sequences are expanded
and \c's should not be recognized (i.e., not in arguments to the
various printing commands), then a \c is actually treated synonymous
to \U.  The attached patch contains a fix.

While inspecting the code I came across another glitch:  If a \c
occurs in the separator string of a $arr[(pws:...:)...] subscript,
it is not treated like an unrecognized sequence (i.e., replaced by
a "c"), but removed completely.  (Note that ${(p...)...} gets this
right.)  The attached patch also fixes that.

Finally, I've discovered that \c in an argument to a printing command
only suppresses the final newline, but according POSIX it should
suppress all output after the \c, and that's what ksh, bash, and
echo/printf from GNU coreutils do.  So is the current behaviour really
desired, or should I send a patch to change it?

Best regards
Thorsten Dahlheimer

[-- Attachment #2: bsc.patch --]
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Index: Src/utils.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/utils.c,v
retrieving revision 1.78
diff -u -r1.78 utils.c
--- Src/utils.c	31 Mar 2005 09:54:59 -0000	1.78
+++ Src/utils.c	24 Jul 2005 00:38:16 -0000
@@ -3611,6 +3611,7 @@
 		    *misc = 1;
 		    break;
 		}
+		goto def;
 	    case 'u':
 	    case 'U':
 	    	wval = 0;
Index: Src/params.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/params.c,v
retrieving revision 1.98
diff -u -r1.98 params.c
--- Src/params.c	8 Apr 2005 16:42:58 -0000	1.98
+++ Src/params.c	24 Jul 2005 00:37:52 -0000
@@ -1002,7 +1002,7 @@
 		    goto flagerr;
 		sav = *t;
 		*t = '\0';
-		sep = escapes ? getkeystring(s + 1, &waste, 1, &waste) :
+		sep = escapes ? getkeystring(s + 1, &waste, 3, NULL) :
 				dupstring(s + 1);
 		*t = sav;
 		s = t;

Re: PATCH: Expansion of \c escape sequences

[Wayne Davison]

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Thanks for the \c fixes and your earlier Makefile.in patch -- I've
checked them into CVS (and I improved the function-comment for
getkeystring() while I was at it).

On Sun, Jul 24, 2005 at 04:15:12AM +0200, Thorsten Dahlheimer wrote:
> Finally, I've discovered that \c in an argument to a printing command
> only suppresses the final newline, but according POSIX it should
> suppress all output after the \c, and that's what ksh, bash, and
> echo/printf from GNU coreutils do.

I'm curious which version of coreutils behaves that way?  I've got 5.2.1
on my system, and it behaves as zsh does.  If we want to change the
behavior, the attached patch should handle it.

..wayne..

[-- Attachment #2: backslash-c.patch --]
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--- Src/utils.c	24 Jul 2005 05:19:58 -0000	1.80
+++ Src/utils.c	24 Jul 2005 05:42:08 -0000
@@ -3611,7 +3611,9 @@ getkeystring(char *s, int *len, int from
 	    case 'c':
 		if (fromwhere < 2) {
 		    *misc = 1;
-		    break;
+		    *t = '\0';
+		    *len = t - buf;
+		    return buf;
 		}
 		goto def;
 	    case 'u':

Re: PATCH: Expansion of \c escape sequences

[Thorsten Dahlheimer]

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Wayne Davison wrote:
> I'm curious which version of coreutils behaves that way?  I've got 5.2.1
> on my system, and it behaves as zsh does.

Indeed, echo seems to have been changed after the 5.2.1 release (I tested
with 5.3.0).  Printf behaves as I described even in 5.2.1, though.

> If we want to change the
> behavior, the attached patch should handle it.

Not quite, since it doesn't handle these cases:

%/usr/bin/echo -e 'a\c' b
a
%/usr/bin/printf '%s\c%s' a b c
a
%/usr/bin/printf '%b %b\n' a b 'c\c' d e
a b
c

I've attached an extended patch that should do this.

Regards,
Thorsten Dahlheimer

[-- Attachment #2: backslash-c_2.patch --]
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Index: Src/builtin.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/builtin.c,v
retrieving revision 1.140
diff -u -p -r1.140 builtin.c
--- Src/builtin.c	17 Jun 2005 08:37:46 -0000	1.140
+++ Src/builtin.c	24 Jul 2005 17:39:28 -0000
@@ -3284,7 +3284,7 @@ int
 bin_print(char *name, char **args, Options ops, int func)
 {
     int flen, width, prec, type, argc, n, narg;
-    int nnl = 0, ret = 0, maxarg = 0;
+    int nnl = 0, ret = 0, maxarg = 0, fmtbsc = 0;
     int flags[5], *len;
     char *start, *endptr, *c, *d, *flag, *buf, spec[13], *fmt = NULL;
     char **first, *curarg, *flagch = "0+- #", save = '\0', nullstr = '\0';
@@ -3313,7 +3313,7 @@ bin_print(char *name, char **args, Optio
     else if (OPT_HASARG(ops,'f'))
 	fmt = OPT_ARG(ops,'f');
     if (fmt)
-	fmt = getkeystring(fmt, &flen, OPT_ISSET(ops,'b') ? 2 : 0, &nnl);
+	fmt = getkeystring(fmt, &flen, OPT_ISSET(ops,'b') ? 2 : 0, &fmtbsc);
 
     first = args;
     
@@ -3349,10 +3349,15 @@ bin_print(char *name, char **args, Optio
 	    (!OPT_ISSET(ops,'e') && 
 	     (OPT_ISSET(ops,'R') || OPT_ISSET(ops,'r') || OPT_ISSET(ops,'E'))))
 	    unmetafy(args[n], &len[n]);
-	else
+	else {
 	    args[n] = getkeystring(args[n], &len[n], OPT_ISSET(ops,'b') ? 2 :
 				   (func != BIN_ECHO && !OPT_ISSET(ops,'e')),
 				   &nnl);
+	    if (nnl) {
+		args[n + 1] = NULL;
+		argc = n + 1;
+	    }
+	}
 	/* -P option -- interpret as a prompt sequence */
 	if(OPT_ISSET(ops,'P')) {
 	    /*
@@ -3754,6 +3759,8 @@ bin_print(char *name, char **args, Optio
 		    if (width < 0 && l < -width)
 		    	printf("%*c", -width - l, ' ');
 		    count += l;
+		    if (nnl)
+			goto printf_finished;
 		}
 		break;
 	    case 'q':
@@ -3854,8 +3861,9 @@ bin_print(char *name, char **args, Optio
 
     	if (maxarg) args = first + maxarg;
 	/* if there are remaining args, reuse format string */
-    } while (*args && args != first && !OPT_ISSET(ops,'r'));
+    } while (*args && args != first && !fmtbsc && !OPT_ISSET(ops,'r'));
 
+printf_finished:
     if (OPT_ISSET(ops,'z') || OPT_ISSET(ops,'s')) {
 #ifdef HAVE_OPEN_MEMSTREAM
 	putc(0, fout);
Index: Src/utils.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/utils.c,v
retrieving revision 1.80
diff -u -p -r1.80 utils.c
--- Src/utils.c	24 Jul 2005 05:19:58 -0000	1.80
+++ Src/utils.c	24 Jul 2005 17:40:03 -0000
@@ -3611,7 +3611,9 @@ getkeystring(char *s, int *len, int from
 	    case 'c':
 		if (fromwhere < 2) {
 		    *misc = 1;
-		    break;
+		    *t = '\0';
+		    *len = t - buf;
+		    return buf;
 		}
 		goto def;
 	    case 'u':

Re: PATCH: Expansion of \c escape sequences

[Wayne Davison]

On Sun, Jul 24, 2005 at 08:09:40PM +0200, Thorsten Dahlheimer wrote:
> Not quite, since it doesn't handle these cases: [...]
> I've attached an extended patch that should do this.

Very nice.  I tweaked it just a bit, and checked it in.  Thanks!

..wayne..